#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

#define PERM 0644

int bufsize=1;

int copyfile(const char *name1, const char *name2)
{

  int infile, outfile;
  ssize_t nread;
  char buffer[1024];

  if ((infile = open(name1, O_RDONLY))== -1)
	return(-1);	/* error on open infile */

  if ((outfile = open(name2, O_WRONLY | O_CREAT | O_TRUNC, PERM))== -1)
  {
	close(infile);
	return(-2);	/* error on open outfile */
  }

  while ( (nread=read(infile, buffer, bufsize)) > 0)
  {
	if (write(outfile, buffer, nread) < nread)
	{
	  close(infile);
	  close(outfile);
	  return(-3);	/* error on write */
	}
  }

close(infile);
close(outfile);

if (nread == -1)
  return(-4);		/* error on final read */
else
  return (0);

}

main(int argc, char **argv)
{
/*
  printf("argc is %d \n", argc);
  for (int i=0; i< argc; i++)
    printf("argv[%d]  is %s \n", i, argv[i]);
*/
    
/*  printf("BUFSIZ is %d  \n", BUFSIZ); */

  if (argc != 4){
	printf("usage: %s infile outfile bufsize\n", argv[0]);
	exit(0);
  }

  bufsize = atoi(argv[3]);
  copyfile(argv[1],argv[2]);
}